(61) باب تَخْفِيفِ الإِمَامِ فِي الْقِيَامِ وَإِتْمَامِ الرُّكُوعِ وَالسُّجُودِ
Narrated Abu Mas`ud:
A man came and said, "O Allah's Messenger (ﷺ)! By Allah, I keep away from the morning prayer only because So and so prolongs the prayer when he leads us in it." The narrator said, "I never saw Allah's Apostle more furious in giving advice than he was at that time. He then said, "Some of you make people dislike good deeds (the prayer). So whoever among you leads the people in prayer should shorten it because among them are the weak, the old and the needy."
Reference: Sahih al-Bukhari 702
In-book reference: Book 10, Hadith 97
USC-MSA web (English) reference(deprecated numbering scheme): Vol. 1, Book 11, Hadith 670